Work

Gravitational waves in ultra-slow-roll and their anisotropy at two loops

Year: 2025

Type: article

Abstract: We compute the non-Gaussian corrections to the energy density and anisotropies of gravitational waves induced during the radiation era after an ultra-slow-roll phase of inflation by using a diagrammatic approach, and present the corresponding Feynman rules. Our two-loop calculation includes both the intrinsic non-Gaussianity of the inflaton perturbation δϕ and the non-Gaussianity arising from the nonlinear relation between the latter and the curvature perturbation ℛ, which we find to be subdominant with respect to the former. We apply our formalism to an analytical model in which the ultra-slow-roll phase is followed by a constant-roll stage with a nonvanishing second slow-roll parameter η , and address the renormalization of the one-loop scalar power spectrum in this scenario.

Source: Journal of Cosmology and Astroparticle Physics

DOI: 10.1088/1475-7516/2025/04/026

Authors: Juan Álvarez Ruiz, Julián Rey

Institutions: Universidade de Santiago de Compostela, Deutsches Elektronen-Synchrotron DESY

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,290

Funder: Deutsche Forschungsgemeinschaft